Field
The disclosed concept relates generally to circuit interrupters, and in particular, to self-testing circuit interrupters.
Background Information
Circuit interrupters, such as for example and without limitation, circuit breakers, are typically used to protect electrical circuitry from damage due to an overcurrent condition, such as an overload condition, a short circuit, or another fault condition, such as an arc fault or a ground fault. Circuit breakers typically include separable contacts. The separable contacts may be operated either manually by way of an operator handle or automatically in response to a detected fault condition. Typically, such circuit breakers include an operating mechanism, which is designed to rapidly open the separable contacts, and a trip mechanism, such as a trip unit, which senses a number of fault conditions to trip the breaker automatically. Upon sensing a fault condition, the trip unit trips the operating mechanism to a trip state, which moves the separable contacts to their open position.
An existing ground fault circuit interrupter (GFCI) circuit 100 is shown in FIG. 1. The GFCI circuit 100 is structured to detect a ground fault on a protected circuit and trip open separable contacts 102 in response to the detected ground fault. An existing GFCI monitor circuit 110 is shown in FIG. 2. The GFCI monitor circuit 110 is structured to monitor the functional status of a GFCI circuit by performing a self-test on a circuit interrupter. However, the GFCI circuit of FIG. 1 and the GFCI monitor circuit of FIG. 2 have not previously been used together in a circuit interrupter.
Furthermore, UL943 includes a self-test requirement, effective on Jun. 29, 2015. The GFCI circuit of FIG. 1 does not comply with UL943 because it does not have a self-test capability.
The GFCI circuit 100 of FIG. 1 and the GFCI monitor circuit 110 of FIG. 2 both require power to operate. The GFCI circuit 100 of FIG. 1 includes a standard bridge rectifier 104. However, if any of the diodes fail in the bridge rectifier, the power to the GFCI circuit 100 would be compromised. A power supply is not shown for the GFCI monitor circuit 110 of FIG. 2, but if a standard bridge rectifier were used to provide power to the GFCI monitor circuit 110 of FIG. 2, a diode failure could compromise the power to the GFCI monitor circuit 110 of FIG. 2. If a GFCI circuit or a GFCI monitor circuit loses power, it becomes ineffective. Reliable power is therefore desirable for GFCI circuits and GFCI monitor circuits.
There is therefore a room for improvement in circuit interrupters.